Description

A steady-state microchannel split-system simulation model has been developed based on
previous research at the ACRC. This model was utilized as a design tool to optimize a
microchannel split system with the goal of minimizing TEWI, or total equivalent warming
impact. The system components were then selected and the optimized microchannel heat
exchangers were fabricated. Next, the entire system was assembled and extensive tests were run
at steady state conditions over a wide range of outdoor ambient conditions in a calorimeter test
facility. The experimental results have been compared to the simulations for the purpose of
model refinement and its eventual validation. The full system model overpredicts the total
capacity of the system with a minimum error of 0.2%, a mean error of 5%, and a maximum error
of 11 %. The evaporator submodel overpredicts the total capacity as well, with a minimum error
of 0.7%, a mean error of 7%, and a maximum error of 11%. The condenser submodel also
overpredicts with a minimum error of 0.5%, a mean error of 2%, and a maximum error of 6%. A
major reason for the lower accuracy with the evaporator is because of the refrigerant
maldisribution observed in the experiments. The model assumes perfect distribution, hence one
reason for the overprediction of the system's capacity.

Issue Date:

1999-03

Publisher:

Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.